Why in medium voltage system(3.3kv to 33kv, neutral is
earthed with either resistance, reactance or neutral
grounding resistance?
Answer Posted / anwar
To limit the Fault current,it has to be conencted to be
earthed .
| Is This Answer Correct ? | 0 Yes | 0 No |
Post New Answer View All Answers
We have drive feeding an output contactor for a 5000 hp motor @ 5kV application. The motor FLA is 629amps x 1.25% service factor = 786.25 amps The cable that we current have in place between the drive and the output contactor is 350kcmil- MV-105 (parallel cables). Per the NEC table 310.60 (C) (69). This show the cable ampacity is at 615 amps per cable for a rating of 1230 amps. We have derated the cable for the cable tray and the multiple cables application and our calculations show that after the correction factor factor we are at 922amps. 1230 amps x .75% correction factor factor = 922.5 amps. The customer is driving us to then use another safety factor of .25% off of the already derated cable. Can you please provide a longhand calculation for your solution on this application?
What are m circles?
How to calculate multiplication factor in kva example 500kva ans pls ?
What is time invariant system?
why +24 v and -48 v give to BTS? If -48v protect from surge then why we not use -24 v?
Why should be the frequency 50 hz 60hz only why not others like 45, 95 56 or anything , why should we maintain the frequency constant if so why it is only 50 hz 60hz?
How do we calculate transformer oil in liter from the rating of the transformer.
What are the main significances of root locus?
what are the stresses in circuit breakers ?
Define branch?
wow to calculate the transformer rating(KVA)
what is the use of commutator in dc motor if we supply ac ? commutator is used to convert ac to dc.and it is used to arrange the flux in unidirectional in case of dc supply. if we give ac as supply to dc motor what is the use of commutator?
what do you mean by type zero control sytem ?Give an practical example of type zero contol sytem?
What is vacuum circuit breaker.define with cause and where be use it device?
A 230V dc shunt wound motor has an armature resistance of 0,15Ω.When operating on no load at 650 rev/min the armature current is 6A . The motor takes a full load current of 85A. Calculate the full load speed if the field flux is (i) maintained constant (ii)reduced by 0,03